infra_generated_artifact_freshness_gate: CI gate for generated-artifact freshness (`types.ts` + `ui/public/docs`)

[SoundMindsAI]

Why

Two tracked generated artifacts drift silently between the feature that should regenerate them and the next feature that happens to run the generator, because nothing in CI fails when a committed copy is stale.

• Problem: ui/src/lib/types.ts (regenerated from the backend OpenAPI via pnpm types:gen) and ui/public/docs/*.md (copied from docs/08_guides/*.md via node scripts/copy-docs.mjs) have no freshness gate. During feat_overnight_autopilot, a routine pnpm types:gen regenerated ~818 lines of types.ts that had accumulated drift from previously-merged features (Solr schemas, the _SourceBreakdown.click UBI bucket), and copy-docs revealed tutorial-first-study.md had never been re-synced after the Solr "Path C" section merged.
• Outcome: CI fails a PR whose committed types.ts does not match what the live OpenAPI schema would produce, and whose ui/public/docs/* copies do not match their docs/08_guides/* sources. Drift is caught at the PR that introduces it, not laundered into an unrelated later PR's diff.
• Non-goal: This feature does not auto-commit regenerated artifacts, does not change what the artifacts contain, and does not add any runtime behavior. It is a CI guard plus the minimal tooling needed to run the regeneration deterministically and offline.

Status

• Stage: PLAN
• Priority: (see idea file)

Definition of done

Spec defines AC-1: copy-docs gate catches a stale public doc, AC-2: copy-docs gate passes on an up-to-date tree, AC-3: copy-docs gate is reachable on a docs-only PR, AC-4: offline OpenAPI export runs with no live services, AC-5: openapi.json snapshot freshness gate catches a schema change, AC-6: types.ts gate catches drift against the snapshot, AC-7: regeneration is byte-deterministic across runners, AC-8: banner is source-invariant, AC-9: gate catches an untracked generated file, AC-10: Phase 2 one-paste fix command makes the gates green, AC-11: removed/renamed guide is pruned from public docs. Each must pass before merge.

Artifacts

• Idea: docs/00_overview/planned_features/02_mvp2/infra_generated_artifact_freshness_gate/idea.md
• Feature spec: docs/00_overview/planned_features/02_mvp2/infra_generated_artifact_freshness_gate/feature_spec.md
• Implementation plan: docs/00_overview/planned_features/02_mvp2/infra_generated_artifact_freshness_gate/implementation_plan.md

How to execute

The folder has both feature_spec.md and implementation_plan.md — both cross-model reviewed. Ready to ship:

/impl-execute docs/00_overview/planned_features/02_mvp2/infra_generated_artifact_freshness_gate/implementation_plan.md --all

--all runs the full story sequence end-to-end with per-story verification gates, phase-gate cross-model reviews via GPT-5.5, test coverage audit, push, PR creation, CI watch, Gemini Code Assist adjudication, and final cross-model review. The PR is opened but NOT merged — you merge it manually after review.

Notes

This issue is part of the MVP2 backlog issue-coverage sweep (2026-06-02) — every active MVP2 folder should have a tracking issue so external contributors can discover the work without grep-ing the planned-features tree. If you pick this up, drop a comment so others don't duplicate; if you find the linked idea/spec stale, run /idea-preflight first to refresh it.